This invention is an apparatus and process used to reduce the occurrence of scale and biomass formation in water systems or aqueous systems.
The cause of scaling within water pipes is a gradual buildup of dense and adherent calcium carbonate deposits. Calcium carbonate formation or precipitation starts with carbon dioxide in air. It is one of the most common natural gases derived from respiration, fuel emission and photosynthesis. When it dissolves in water (rain or moisture), it forms weak carbonic acid. Carbonic acid in rain and ground water dissolves lime stone sedimentary rock (calcium carbonate) to form calcium bicarbonate. Calcium bicarbonate is a soluble form of calcium carbonate. Its formation occurs at neutral pH (6 and 8). The reason that calcium carbonate is important in water treatment is that it has a very low solubility, and its solubility decreases with an increase in temperature. All water cooled heat transfer equipment is vulnerable to calcium carbonate fouling or deposition due to lower calcium carbonate solubility on the heat transfer surface than in the cooler bulk water.
When calcium carbonate crystallizes on a heated surface, the crystals line up to form a structure similar to a brick wall, and it is dense and impervious to heat transfer. Its poor thermal conductivity impedes heat transfer, which causes a waste in energy and creates a potential danger of boiler tube overheat and the possibility of a compressor shut-down in air-conditioning equipment. When crystals line up in an orderly manner as previously described, they form rocklike, rigid, dense structures. Certain structures are denser and more adherent than others. In the case of calcium carbonate formed on heat transfer surfaces, the structure is primarily in the form of calcite with a small amount of aragonite. There is a third uncommon type formed, vaterite, which is hexagonal in molecular structure.